Spindle Variant Primary Diffuse Large B Cell Lymphoma of the Colon: Case Report and Literature Review.

Diffuse large B cell lymphoma (DLBCL) with spindle cell morphology is a rare variant that can be seen in extranodal regions. Because the spindle cell dominant morphology in lymphoma is extremely unusual, the diagnosis can easily be missed in many organ systems. We present a case of an 82-year-old male patient with complaints of abdominal pain and swelling. He operated with the preliminary diagnosis of cecum tumor and ileum perforation. Tumoral proliferation was observed originating from the submucosa and infiltrating the muscularis propria, with the features of mostly spindle-shaped, having round-shaped nuclei in some of the cells, and having relatively narrow cytoplasm. A panel of immunohistochemical stains were performed to rule out the possibilities of sarcoma, carcinoma, or melanoma. Diffuse strong positive reaction was observed for CD45, CD20, CD19, CD22, Pax5, and CD30. The case was reported as spindle cell variant of DLBCL based on the present findings. As far as we know, this is the first case described in the colon. We emphasize that pathologists should be reminded of lymphoma as a differential diagnosis of spindle cell tumors.